[mc] Remote support for MC_deadlock_check() using MC_MESSAGE_DEADLOCK_CHECK IPC message

[simgrid.git] / src / mc / mc_page_snapshot.cpp

diff --git a/src/mc/mc_page_snapshot.cpp b/src/mc/mc_page_snapshot.cpp
index dcf0d9b..c8aa50f 100644 (file)
--- a/src/mc/mc_page_snapshot.cpp
+++ b/src/mc/mc_page_snapshot.cpp
@@ -1,3 +1,5 @@
+#include <unistd.h> // pread, pwrite
+
 #include "mc_page_store.h"
 #include "mc_mmu.h"
 #include "mc_private.h"
@@ -20,10 +22,17 @@ extern "C" {
  *  @param reference_pages Snapshot page numbers of the previous soft_dirty_reset (or NULL)
  *  @return                Snapshot page numbers of this new snapshot
  */
-size_t* mc_take_page_snapshot_region(void* data, size_t page_count, uint64_t* pagemap, size_t* reference_pages)
+size_t* mc_take_page_snapshot_region(mc_process_t process,
+  void* data, size_t page_count, uint64_t* pagemap, size_t* reference_pages)
 {
   size_t* pagenos = (size_t*) malloc(page_count * sizeof(size_t));
 
+  const bool is_self = MC_process_is_self(process);
+
+  void* temp = NULL;
+  if (!is_self)
+    temp = malloc(xbt_pagesize);
+
   for (size_t i=0; i!=page_count; ++i) {
     bool softclean = pagemap && !(pagemap[i] & SOFT_DIRTY);
     if (softclean && reference_pages) {
@@ -34,10 +43,27 @@ size_t* mc_take_page_snapshot_region(void* data, size_t page_count, uint64_t* pa
       // Otherwise, we need to store the page the hard way
       // (by reading its content):
       void* page = (char*) data + (i << xbt_pagebits);
-      pagenos[i] = mc_model_checker->pages->store_page(page);
+      xbt_assert(mc_page_offset(page)==0, "Not at the beginning of a page");
+      void* page_data;
+      if (is_self) {
+        page_data = page;
+      } else {
+        /* Adding another copy (and a syscall) will probably slow things a lot.
+           TODO, optimize this somehow (at least by grouping the syscalls)
+           if needed. Either:
+            - reduce the number of syscalls;
+            - let the application snapshot itself;
+            - move the segments in shared memory (this will break `fork` however).
+        */
+        page_data = temp;
+        MC_process_read(process, MC_ADDRESS_SPACE_READ_FLAGS_NONE,
+          temp, page, xbt_pagesize, MC_PROCESS_INDEX_DISABLED);
+      }
+      pagenos[i] = mc_model_checker->pages->store_page(page_data);
     }
   }
 
+  free(temp);
   return pagenos;
 }
 
@@ -59,7 +85,8 @@ void mc_free_page_snapshot_region(size_t* pagenos, size_t page_count)
  *  @param pagemap         Linux kernel pagemap values fot this region (or NULL)
  *  @param reference_pages Snapshot page numbers of the previous soft_dirty_reset (or NULL)
  */
-void mc_restore_page_snapshot_region(void* start_addr, size_t page_count, size_t* pagenos, uint64_t* pagemap, size_t* reference_pagenos)
+void mc_restore_page_snapshot_region(mc_process_t process,
+  void* start_addr, size_t page_count, size_t* pagenos, uint64_t* pagemap, size_t* reference_pagenos)
 {
   for (size_t i=0; i!=page_count; ++i) {
 
@@ -73,7 +100,7 @@ void mc_restore_page_snapshot_region(void* start_addr, size_t page_count, size_t
     // Otherwise, copy the page:
     void* target_page = mc_page_from_number(start_addr, i);
     const void* source_page = mc_model_checker->pages->get_page(pagenos[i]);
-    memcpy(target_page, source_page, xbt_pagesize);
+    MC_process_write(process, source_page, target_page, xbt_pagesize);
   }
 }
 
@@ -163,6 +190,8 @@ mc_mem_region_t mc_region_new_sparse(mc_region_type_t region_type,
   void *start_addr, void* permanent_addr, size_t size,
   mc_mem_region_t ref_reg)
 {
+  mc_process_t process = &mc_model_checker->process;
+
   mc_mem_region_t region = xbt_new(s_mc_mem_region_t, 1);
   region->region_type = region_type;
   region->storage_type = MC_REGION_STORAGE_TYPE_CHUNKED;
@@ -177,8 +206,9 @@ mc_mem_region_t mc_region_new_sparse(mc_region_type_t region_type,
   size_t page_count = mc_page_count(size);
 
   uint64_t* pagemap = NULL;
-  if (_sg_mc_soft_dirty && mc_model_checker->parent_snapshot) {
-      pagemap = (uint64_t*) mmalloc_no_memset(mc_heap, sizeof(uint64_t) * page_count);
+  if (_sg_mc_soft_dirty && mc_model_checker->parent_snapshot &&
+      MC_process_is_self(process)) {
+      pagemap = (uint64_t*) malloc_no_memset(sizeof(uint64_t) * page_count);
       mc_read_pagemap(pagemap, mc_page_number(NULL, permanent_addr), page_count);
   }
 
@@ -187,7 +217,7 @@ mc_mem_region_t mc_region_new_sparse(mc_region_type_t region_type,
     reg_page_numbers = ref_reg->chunked.page_numbers;
 
   // Take incremental snapshot:
-  region->chunked.page_numbers = mc_take_page_snapshot_region(
+  region->chunked.page_numbers = mc_take_page_snapshot_region(process,
     permanent_addr, page_count, pagemap, reg_page_numbers);
 
   if(pagemap) {
@@ -196,7 +226,7 @@ mc_mem_region_t mc_region_new_sparse(mc_region_type_t region_type,
   return region;
 }
 
-void mc_region_restore_sparse(mc_mem_region_t reg, mc_mem_region_t ref_reg)
+void mc_region_restore_sparse(mc_process_t process, mc_mem_region_t reg, mc_mem_region_t ref_reg)
 {
   xbt_assert((((uintptr_t)reg->permanent_addr) & (xbt_pagesize-1)) == 0,
     "Not at the beginning of a page");
@@ -205,8 +235,9 @@ void mc_region_restore_sparse(mc_mem_region_t reg, mc_mem_region_t ref_reg)
   uint64_t* pagemap = NULL;
 
   // Read soft-dirty bits if necessary in order to know which pages have changed:
-  if (_sg_mc_soft_dirty && mc_model_checker->parent_snapshot) {
-    pagemap = (uint64_t*) mmalloc_no_memset(mc_heap, sizeof(uint64_t) * page_count);
+  if (_sg_mc_soft_dirty && mc_model_checker->parent_snapshot
+      && MC_process_is_self(process)) {
+    pagemap = (uint64_t*) malloc_no_memset(sizeof(uint64_t) * page_count);
     mc_read_pagemap(pagemap, mc_page_number(NULL, reg->permanent_addr), page_count);
   }
 
@@ -215,7 +246,8 @@ void mc_region_restore_sparse(mc_mem_region_t reg, mc_mem_region_t ref_reg)
   if (ref_reg && ref_reg->storage_type == MC_REGION_STORAGE_TYPE_CHUNKED)
     reg_page_numbers = ref_reg->chunked.page_numbers;
 
-  mc_restore_page_snapshot_region(reg->permanent_addr, page_count, reg->chunked.page_numbers,
+  mc_restore_page_snapshot_region(process,
+    reg->permanent_addr, page_count, reg->chunked.page_numbers,
     pagemap, reg_page_numbers);
 
   if(pagemap) {